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US 8,372,362 B2Granted
Method and system for controlling mercury emissions from coal-fired thermal processes
AssigneeADA-ES, Inc.
InventorsMichael Durham, Nina Bergan French, Ramon E. Bisque, Kenneth E. Baldrey
Life of this patent
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Abstract
The present disclosure is directed to the use of elemental or speciated iodine to control total mercury emissions.
Claims49
A method, comprising:
- in a mercury-containing gas stream comprising vapor-phase mercury and vapor-phase iodine and having a temperature ranging from about 325 to about 450° C., the vapor-phase iodine being derived, at least in part, from an iodine-containing additive, separating at least about 50% of the vapor-phase mercury from the mercury-containing gas stream, wherein at least one of the following is true:
- (i) the mercury-containing gas stream comprises about 3.5 ppmw or less vapor-phase iodine;
- (ii) in the mercury-containing gas stream, a molar ratio of vapor-phase iodine to vapor-phase mercury is no more than about 600;
- (iii) at an air preheater outlet, a concentration of vapor-phase iodine ranges from about 0.1 to about 10 ppmw;
- and
- (iv) a concentration of the vapor-phase iodine is about 30 ppmw or less relative to a weight of a solid mercury-containing feed material producing the vapor-phase mercury.
3 more elements
A method, comprising:
- contacting a mercury-containing solid feed material with an iodine-containing additive to form a treated feed material, wherein an iodine concentration of the iodine-containing additive relative to a weight of the feed material is about 30 ppmw or less;
- thereafter generating, from the treated feed material, a mercury-containing gas stream comprising vapor-phase mercury and iodine;
- and
- removing at least about 50% or more of the mercury from the mercury-containing gas stream.
1 more element
A method, comprising:
- contacting a solid mercury-containing feed material with an iodine-containing additive to form a treated feed material;
- generating, from the treated feed material, a mercury-containing gas stream comprising vapor-phase mercury and iodine, wherein the vapor-phase iodine comprises both a hydrogen-iodine species and diatomic iodide and wherein a molecular ratio of diatomic iodide to the hydrogen-iodine species is at least about 25:1;
- and
- removing at least most of the mercury from the mercury-containing gas stream.
1 more element
Dependencies are inferred from the claim text.